Plunger-equalizer.



- A.KM."G0YLE. v

l PLUNGERBQUALIZER.

APPL'IOATioN FILED 11114114.1905. v l 95;"1558`552;l I D Patented Apr.26,1910.

3 SHEETS-SHEET 1.

s f A ATTO NEY.

A A'. M; COYLE.

PLUNGER EQUALIZER.

APPLICATION FILED JULY 14, 1905.

Patented Apr. 26,19170.

` 3 SHEETS-SHEET 2.

wnNEssEs:

` Patented Apr,26,191o.

l a amus-SHEET a.

WITNESSES ATTORNEY UNTTED sTATEs PATENT onFIoE.

ANDREW M. COYLE, OF NEW YORK, N. Y., ASSIGNOR TO OTIS ELEVATOR COMPANY,OIEY JERSEY CITY, NEWV JERSEY, A CORPORATION 0F NEW JERSEY.

PLUNGER-EQUALIZER.

Application filed July 14, 1905.

To all whom it may concern:

Be it known that I, ANDREW M. CorLE, a citi/.en ot the United States,residing at New York city, in the county of New York and State of NewYork, have invcnted'a new and useful Improvement in Flnnger-llqualizers,ot' which the following is a siiecilication.

My invention relates to plunger cqualizing mechanism and has tor itsobject the provision of vsimplified and etlicient means for cqualizingthe motion of a plurality ot plungers to elt'ect a uniform lifting of aload by the plungcrs irrespective of the uneven distribution of saidload.

More particularly it the object.- of my in vention to provide improvedvalves and gearing' and means for automatically Operating the same toregulate. the How of fluid under pressure to a plurality of plungers andeffect the lifting of said plungers at substantially equalvelocitiesirrespective of the load carried by the various plungers. i Y

To these and other-ends appearing hereinafter. my invention consists ofthe combination, location, construction. and arrangement of the variouspartsy all as more fully explained in the following description andspecitically pointed out in the claims.

ln the acconn'ianying drawings, Figure 1 is a plan view and Fig. 2 anelevation of a platform and hydraulic m.hanism for 0perating the same;Fig. is a sectional view of the 'preferred form of equalizing valve andalso shows the arrangement otditl'erential gears by which .said valve isoperated ;'A

Fig. 3 is a view ot the ditl'erential gears.

taken on the line un of Fig. 3; Figpl is an elevation of Fig. 3 with aportion broken away to show certain details; Figs. 5 and 6 showrespectively a plan and an elevation' of a modified form of myinvention; Fig. 7 shows a detail of the same.; and Figs. 8, 9 and 10are, respectively, a plan, an elevation and a detail view of myinvention applied to valves of ordinary construction.

1 designates a platform to which are secured the plungers, 2, 2', 3, 3'near the four corners of the same. These pluugers are adapted to move inthe hydraulic cylinders` 10, 11, 12, 13 in a wel] known manner. Thesecylinders are fed respectively by the branch pipes 14, 15, 17 and 1G.Between the pipes 14 and 15 is connected an equalizilig valve'mcchanisln18 and between the pipes 16 and 17 is placed a similar equalizing valveSpeccaton of Letters Patent.

Patented Apr. 26, 1910. Serial No. 269,586.

mechanism 19. The valves 18 and 19 are connected by the pipes 22 and 23with the main equalizing valve mechanisnr 2() which is connected to themain supply pipe 21. I associate certain differential gearing with thesevalves and provide. automatic means for operating the same so that thesupply of tluid to the plunger cylinders shall be. so varied when anyone of the plungers tends to assume a posit-ion dili'erent from thatrequired by the conditions .of the apparatus, that the platform willalways remain substanti-ally level. For instance if one end of theplatform beheavily loaded and the other end lightly loaded, the formerend will tend tolag behind the latter when the platform is beingliftedand consequently a good landing couldnot he made nor could theload be well carried. A

In Fig. 1 I have shown three differential gear mechanisms 24, 25 and 26connected in line and to each other by the shafts 26, 27, 28 and 29.suitable standards 30 (Fig. 6) heilig provided with bearings for theseshafts. rigidly secured the bevel gears 31 and and at the ends of theshaft 27 are secured .the bevel gears 33 and 34. T o the inner ends ofthe shafts 28 and 29 are fastened the bevel gears and 36, respectively,to face the gears 31 and 34. 'lhegears 32 and 33 face each other in asimilar manner. Between each Aset ofV gears, however, there issufficient space for a planetary bevel gear to be placed with its axisat right angles to the shafts mentioned and mounted 0n bearings in linewithsaid shafts. 1n Fig. 3a is shown a bearing 183 for the arm 37 whichcarries the gear 39. The bearings for the gears 32 and 33 are At theends of the shaftl 2G are` indicated at 182 and 182', respectively.The\95 hearings for the arm 37 and the gears 32, 33, are 1n ahnementwith each other. These planetary gears are indicated by the referencenumber 38, 39 and 40 and are always in mesh withthc gears 35, 31 and 32,33 and A34, 36, respectively, at the ends of the shafts.

4, respectively. The belt et is fastenedl to one' corner of the platform1 at 56`and passes downwardly under the pulley 6 and then to L the righthorizontally (Fig. 2)v under the pulley 47 on the shaft 29 and continuesvover the pulley 9 toa weight 55. The belt 5 is fastened at 57 near theopposite corner andpasses vertically downward under the pulley 7 andover the pulley 46 on the shaft 27 to' the weight 54. At the other endof the platjgf form the belts 48 and 49 are attached respec- -bepreferable in some cases. In either case it is apparent that there is atensional recipl rocating connection between the bottom of preventleakage.

the platform and the differential mechanlsms.

If the fluid is admitted to the three valves and the four cylinderssimultaneously by opening the supply pipe 21, the platform will .belifted. lt will be noticed that the belting is so arranged that the fourshafts` will rotate alternately in opposite directions. For instance, ifthe platform be traveling downwardly the shaft 29 will rotateanticlockwise (Fig. 2); shaft 27, clockwise; shaft 26,anti-clockwiseg'and shaft 28 clockwise. It will be readily understoodthat if these shafts rotate with uniform velocities the bevel gearssecured to them will simply rotate the planetary gears 38,` 39 and 40about their centers and not tend to bodily move the same so as tooperate the valves to which they are connected. vBut if one of theshafts revolves at a dilferent rate of speed'than the one next to it theplanetary gears will be moved inl one direction or the' other to movethe valve stem.

Before describing further the operation of the equalizing mechanism, Iwill explain the construction of the valves 19, 2O and 18, one of whichis shown in section in Fig. 3, say the central one of Fig. 1.

62y designates the valve chest through which longitudinally is adaptedto move the valve 65, suitable stuffing boxes in the valve chest beingprovided for lubrication and to The valve chest is provided with fiveannular ports 78, 7 9, 80, 82

-and 83. The central chamber 63 communicates with the pipe 64 whichleads to the supply pipe 21 and also through the valve ports 81 with theinterior of the hollow feo valve 65.

Near the ends of the valve chest 62 are 19 and 18. Check valves 70 and71 are l placed in the separate chambers 73 and 74, I

half covered up. That is, half of the number of holes 76 communicatewith the annular port 78 when the valve 65 is in central position, whilethe otherhalf are closed. In a similar' manner half of the holes 77 arein communication with the annular port 79, half of the holes 93 with theport 82, and half of the holes 94 with the port 83.

The chamber 87 of the check valve box 68 communicates with the chamber73 through the opening 72 but iiuid cannotenter the annular port 78through the chamber below fronnchamber 73 by reason of the check valve70. Chamber 87 also communicates with the chamber below the chamber 74through the opening 92 and liuid can be forced thence into the chamber74 past the check valve 71. The chamber 74 communicates with the port 63through the port 75, half of the port holes 77, the `interior of thecylindrical valve 65, a'nd the valve ports 81.

The operation of the construction thus far described is as follows:Assuming a change valve in the supply pipe to be moved topressure-supplying position d the Yvalves 19, 2O and 18 in their centrapositions, the fluid will flow through the central valve from annularchamber 63 through the holes 81, to v and through half of the holes 76at one end and half of the holes 94 at the other end of the valve 65.The fluid passes also through half the holes 77 on one hand and half theholes 93 on the other hand. The fluid through the holes 77 and 93,however, cannot be forced out ,of the check valveboxes by reason of thecheck valves 71 and 66. The fluid passing through the holes 76 into theannular chamber 78 will lift the check valve .against the force ofgravity and flow into chamber 73, through opening 72 into chamber 87 andthence through the port 23 into the pipe 23 and through the same to thevalve V19. In this valve the fluid enters the central annular chamber 63and passes throu h the check valveboX 68, pipe 16 to the cy inder 13.The fluid also passes from the annular chamber 63 through the openings81,half of the holes 94, chamber 83, port hole 84 into chamber 90, pastthe check valve 67 into the 'chamber 86, port 91, chamber 88,

port 22', pi e 22 to valve 18. Through 'this through the check valve boxG9, pipe 15 to cylinder 11. Ofcourse the fluid passes also through the'check valve box 69 of the* valve 19 to the pipe 17 and cylinder 12, andthrough the check valve box G87', to the pipe 14 and cylinder 10. Eachvalve being in central position the rate of flow of the fluid Will bethe same to each cylinder and the platformlwill be lifted atsubstantially uniform velocities at all points. This will cause thevarious shafts to be rotated at equal rates of speed and consequentlythe planetary gears will simply rotate about their centers as beforeexplained. Suppose, however, that a heavy load is placed over theplungers 3 and 3 at one end of the platform and there be a light orpractically no load at the other end. The end bearing the heavy loadwill tend to lag behind the other end. Therefore, more fluid must besupplied to the valve 19 than tothe valve 18 and this is doneautomatically with my arrangement. The lighter end will travel fasterthan the heavier end and in so doing will rotate the shaft 27 in ananti-clockwise direction faster than the shaftf26 is rotated in aclockwise direction. This will effect a movement of the planetary gear39 bodily to the left and of the valve stem 42 to the right. A largernumber of ports 6 Will then be opened into the annular -port 78 while acorresponding number of the ports 94 will be closed from' communicationwith the port 83. It is,

therefore, seen that iuid will flow at. a 35 greater rate of speed tothe valve 19 and at a less rate of speedf to the valve 18 at this timethanswhen the valve is in central position. In a similar manner if onecorner is more heavily loaded than the one next to it, as for inst-ance,if there'is a heavier load on the plunger 3 than on the plunger 3, 'thecylinder 13 Will receiveimore fluid than the cylinder 12 until theplatform becomes level.

With any unequal load the equalizing action is constantly andgraduallytaking place in the manner 'stated so long as the platform is.

being lifted.

In the opposite direction of the platform, that is when the same isdescending, the most heavily loaded part of the platform will tend todescend the faster. The plunger adjacent that point must therefore be'retarded and this is done automatically by means of the same valves asbefore but-using other portions of the cheek valve boxes and otherelliptic-ally arranged ports in the valve cylinder Of course, in,descending the fluid must be exhausted from the cylinders and in orderto allow the lighter portions of lthe platform to descend at thesamerate of speed as the heavier portions the cylinders under the lighterportionsmust be exhausted faster and those under the heavier port1onsretarded in exhausting. Suppose, then,

that the plungers 2l and 2 are ther'more' to chamber 87, through port92, past-(check valve '71, through chamber 74, port 75, half of theholes 77, portholcs 81, to the exhaust port of the change valve in themain supply pipe 21. The fluid is also exhausting to the supply pipeexhaust port from the cylinders 10 andv 11, through valve 18, pipe 22,chamber 88, port 95, chamber 89, past check valve 66, chamber 85, port96 and annular charnber 82. through half the holes 93, to the ports S1and thence to the supply pipe 21. But when the valve 65 is moved to theleft theholes 93 are throttled while those at 77 will he opened wider.The exhausting of the fluid from the cylinders 1() and 11 is thereforeretarded and that from the cylinders 12 and 13 increased. Thisequalizing action takes place constantly as before. and maintains theplatform substantially level. As in the case of the platform ascending,so

also when the same descends the valves 19 and 18vma v also be operatedto allow the fluid to escape from one cylinder,V as 10, faster than thefiext adjacent one, as 11.

Figs. 5, and 7 show a modified form of valve, three of which areconnected to the )latform lift-ine means Fig. 5) in exact-l f I the samemanner as is done. in F 1 and 2.

But I provide manual means for operating the valves instead of automaticmeans and therefore the check valve mechanism is un Fig. 6 shows thedetails of the valve mech-` on which is littettiacrank arm 103 which hassecured at its' lciuterend a laterally projecting pin 104. From Fig. 5it will be seen that a rod105 is connected to the pin 104 o f the crankarm of each of the valve mecha-nisms so that when said rod is movedlongi- A tudinally the internal sleeve 97 of each valve will be rotatedabout its longitudinal axis.

-It will be noticed further, that each of the valvesmay be movedlongitudinally with out interference with the operation of the crankarms for in such case the squared ends of the shafts will simply slidethrough the 50 set. Suppose the plungersy 2 and 2 are b esquare holes inthe hubs of said arms. The pins 104 may slide in the bar 105. A,

The inner sleeve 97 is rovided with series of circularly arranged holeswhich are adapted to register with corresponding holes in thecylindrical portion of the va ve 65. The valve chest 120 is providedwith ports f 117, 118 and 119 which are shown inFig. 6

l tively, registerin as screw-threaded to receive the ipes 22,64 and 23,respectively, assuming the valve to be the central one of Fig. 5. Thescrewthreaded ports communicate with annular chambers or ports 121, 122and 123 which surround the valve cylinder 65 at the openings therein.

The operation is as follows: Assuming each valve to be in the ositionshown in Fig. 6 the supply Huid wil pass through the ports 118 and 122,the holes 114 and 115 in the valve 65, and holes 108 and 109,respectherewith, into the interior of the cylin rical'sleeve 97. TheHuid ma then pass through the openings 107 an 110in the inner cylinder,openings 113 and 116, respectively, in the outer cylin der, into thechambers 121 and 123 and through the ports 117 and 119, pipes 22 andv23, valves 18 and 19, pipes 14 andv 15 to the cylinders 10 and 11 andpipes 17 and 16, to the cylinders 13 and 12. The fluid cannot passthrough the openings 106 or 111 as they are closed at this time, thatis, they do not register'with the openings 112 or 117 in the outercylinder. Now'by moving the rod 105 longitudinally the openingsshown inFig. 6 may be throttled to any extent desired and therefore the speedwith which` the platform is being lifted may be con' trolledor it maybestopped by rotating the inner sleeve .to entirely -close the circularseries -of holes. It will be seen that when the valve is in centralposition the holes 113 and 116ja-re halfthrottled by the valve seat.Should, therefore, one end of the platform be lifted more rapidly thanthe other due to a lighter load, the planetary gear would be movedbodily and consequently the valvewould be moved longitudinally. Thisoperation would effect a wider opening of one set of ports and athrottling of the other ing lifted faster than the plungers 3 and 3.

)This will eect an automatic movement of the valve to the right. Theopenings 116 `and 110 will be opened wider while those designated by thereference numbers 113 and 107 will be throttled. The fluid can thereforeflow to the valve 19 at a greaterrate'of speed than to the valve 18.This will tend to -equalize the`\rate of -speed at which the plungersare being lifted and therefore maintain the platform substantiallylevel. IVhen the platform descends the reverse movements of the plungerstend to take place, that is, the heavier endwill tend to holes 106 mustregister with the holes 112 and the holes 111 with the holes 117 Incentral'position each of the series of'holes 112 and 117 are halfthrottled by the valve seat.l

In the new position of the valve sleeve, when the valve is moved to theright the exhaust from the valve 18 will be more rapidthan from the'valve 19. The lighter end of the platform wiill then tend to descendImore rapidly and catch u with the loaded end where the exhaust rom thecylinders will be retarded. The nal result will be to keep the platformsubstantiall level..

In Figs. 8, 9 and 10 I ave show-n an application of the equalizing gearsto valves v of ordinary construction. This type of valve 1 s shown, mFig. 10 in section and is what 1s known in elevator practice as athree-Wayfchange valve.

In Fig. 8 I have shown four valves, one

for ,each plunger. Upon vthe shaft 135 which extends vthroughout thelength of the mechanism are fixe bevel ,gears` 136, .137, 138 and 139.'Loosely mounted on said shaft are the bevel gears 140, 141, 142and 143on the hubs of which are secured the pulleys 179,174, 180` and 165.

Fixed to the four corners of the platform 1 are the -belts 171, 173, 161and 162 which pass vertically downward to idle pulle s v170, 172, 164and 163 and then'horizonta yl tp the pulleys 179, 174, 180 and 165, resectlvely. The belts pass under all the Ifast named/pulleys to additionalidle or direction pulleys 178, 175, 181 and 166 and thence to vlveights177, 176, 182and 167, respective y.

The shaft 135 may be manually rotated either bythe gearing 129 andhandle 128 or by means of the handle 130 and shaft 131 arranged at apoint' above the platform but within reach of the operator. This shaft131 has fixed to it a pulley 132 which is connected by'a belt 133 toanother pulley 134 fixed t9 the shaft 135. Upon movement of the shaft135 in a clockwise direction the link 43 -will be moved toward the leftasI move longitudinally in' the valve chest-152.

As shown in Fig. 10 the valves are in central or closed position so thatthe Huid entering the space between the valves from the cylinders`through the supply port 153 can go no farther, nor can Huid from thesupply port- 157 enter the cylinders. If, however, the valve stem 160 ismoved to the right the iuid can pass from the supply port 157 through'the openings 156 in the lining and thence to and through bhe port 153and to the cylinder connected therewith. Therefore when the shaft isturned in a clockwise direction all the change valves will be opened andthe platform will ascend. As it does so, however, the valves will beagain closed by the automatic movement of the planetary gears in theopposite direction. The latter movements of the planetary gears willvary with the'load on the different parts of -the platform, those partsmoving the faster throttling the fluid to the 'nearest cylinders morethan the slower moving` portions. will be seen, however, that the motionof the shaft 135 must be kept up, otherwise thc change valves will beclosed as soon as the platform has moved sufficiently to effectthemovements of the planetaries back to their original positions. If themotion of the shaft 135 is continued manuallyT the motion of theplatform will also continue only stopping`when the plungers have reachedinfedetermined limits- While the platform is moving .thereis always atendency for the loose gears to catch up with the fixed gears and atrates depending upon the distribution of load on the platform, theeffect being to maintain the plat-form substantially level irrespective.of such distribution of load. Of course, when the platform `is allowedto 'descend the'fluid is exhausted from the cylind'er through theexhaust ports 159 of the change valves, to the exhaust pipe 169. Theoperation of the equalizing apparatus would be the same in this caseonly in reverse direction.

While the arrangement shown in Figs. v8, 9 and 10 is not entirelyautomatic it employs ordinary valves and admits of very promptgoverning.

As shown in F ig. 9, the plungers or rams may, 1f desired, be hinged tothe platform, as by ball and socket joints, but ordinarily theiexibility of the platform willv be sufficient to take care of anytendency of an un- 'even load to bend the rams, this tendency beingreduced to'a minimum by the 'use ofjmy invention.

Having thus described my invention and Without limiting myself totheprecise construction of details or arrangement of parts, what I claimand desire to secure by Letters Patent of the United States is:

1. The combination witha platform, of means for'lifting the same, meansfor controlling said lifting-means, 'dierential planetary mechanism foractuating said controlling-means, and means operatively connected to theplatform for throwing said differential mechanism to various positions.

Q. The combination with a platform, of

means for lifting the same, means for controlling' said lifting-means,differential planetary mechanism for actuating said controlling-means,and a reciprocating tensional connection operatively connected with saidplatform and saidA differential mechanism for actuating the latter.

The combination with a platform,A of a plurality of lifting motors andcontrollingmeans therefor, diiferential planetary mechanisms foractuating said controlling-means, and a plurality of tensionalconnections each operatively connected with said platform and adapted toindependently actuate each differential mechanism.

Ll. 'lhe combination with a plat-form, of`

said platform and said differential lnechanism to actuate the latter andthrow said valve to various degreesof opening.

6. The combination with a platform, of a hydraulic motor for lifting thesame, a

Valve for controlling the motor, differential planetary mechanism foroperating said valve, and a reciprocating tensional connectionoperatively connected with said platform and differential mechanism foractuating the latter. A

7. The combination with a platform, of a plurality of lifting hydraulicmotors and valves therefor, a plurality of co-acting differentialplanetary mechanisms for operating said valves, and a plurality oftensional connections each operativelyl connected .with said platformAand differential mechanisms for operating the latter.

v8. The combination with a platform, of

three or more hydraulic plungers connected therewith, hydrauliccylinders for said plungers, valves for controlling the passage of fluidto and from said cylinders, differential gearing arranged in alinementfor actuating said valves to various degrees of opening to vary the rateof flow of fluid `to the various cylinders and means connecting saidplatform and differential gearing for automatically operating thelatter.

9. The combination With a platform, of a plurality of motors for liftingthe same, a plurality of valves for controlling said motors, planetarygearing for actuating said valves, and means connected to the platformfor operating said gearing.

10. The combination with a platform, of a plurality of hydraulic motorsfor moving the same, a plurality of Valves for controlling saidA motors,a plurality of differential planetary mechanisms corresponding in numberto lthe number of valves for actuating said Valves to various degrees ofopening, and means connected With the platform for automaticallyoperating said differential mechanisms. f

11. The combination With a platform, of three or more hydraulic motors,aplurality of valves for controlling said motors, dierential gearingcoperatively connected in alinement with each other for actuating saidvalves to various degrees of opening, and means for operating saiddierential gearing.

12. The combination yWith a platform, of hydraulic motors therefor,valve mechanism for controlling said motors, and planetary y gearingoperating said valve mechanism, the latter being constructed andarranged When operated by'said gearing to simultaneously increase therate of flow of fluid to the motors most heavily loaded and decreasethe: rate of flow to the motors less heavily loaded.

l. The combination With a platform, of hydraulic motors therefor, valvemechanism for controlling said motors, and planetary gearing operatingsaid-valve mechanism, the latter being constructed and arranged Whenoperated by said gearing lto simultaneously increase the rate of flow ofHuid to t-.he motors heavily loaded and decrease 'the rate of flow tothe motors lightly loaded When the platform is being lifted and tocontrol the exhaust reversely When the platform is descending.

14C. The combination with a platform, of distributed hydraulic motorstherefor, valves for controlling said motors, diHerential gearingcomprising a plurality of planetary gears, connections between saidplanetary gears and said valves, and means for actuating saiddifferential gearing to effect an even lifting of the platformirrespective of .the loadv thereon.

' 15. The combination With a platform, of hydraulic motors for liftingthe same, a plurality of valves forffcontrollingsaid motors,

differential gear mechanisms comprising planetary gears andcorresponding in number to the number of said valves and arranged insubstantial alinement with each other, valve-actuating connections'between 'the planetary gear of each of said gear'mechanisms vand eachof said valves, and connections corresponding in number with the numberof hydraulic motors for operating said differential gear mechanisms.'7f3l 16. The combination with a platform, of a plurality of distributedhydraulic motors for lifting said platform, valves for controlling saidmotors, planetar bevel gear' mechanism with connections for operatingsaid valves, and' means for automatically operating said planetary bevelgear mechanism and said valves to maintain the platform substantiallylevel at all times.

17. The combination with a platform, of hydraulic motors therefor,valves for controlling said motors, a plurality of shafts m alinementwith each other, bevel gears secured to both ends of the intermediateshafts and to the inner ends of the outside shafts, planetary bevelgears mounted between each pair of facing bevel gears on said shaftsvalve-actuating means connected to sai planetary'I gears, a pluralit ofWheels one fastened to each of said shafts, a plurality of 90connections one for each of said Wheels and each secured to' theplatform, means for d1- recting said connections, and means for keepingsaid connections taut.

18. The combination 'with a platform, of hydraulic means for moving thesame, valve l mechanism for controlling said moving means com .rising amain valve, check valves, and sets o ports in the main' valve foroperatively connecting the same with the check valves and means forautomatically operating said valve mechanism to simultaneously open oneset-of ports therein and closel another set and place both sets of portsin cooperative relation With half of the number 105 of said checkvalves.

19. The combination with a platform, of hydraulic means for moving thesame, a main valve provided With a plurality of series of supply ports,a corresponding number of supply check valves to coo erate with saidsupply ports, said main va ve having also a plurality `of series ofexhaust ports,

a plurality of exhaust check valves to c0- for moving said main valve tosupply or ex,\

haust position.

20. The combination With a platform, of

hydraulic meansA for moving said platform,

a main valve provided With two series of graduated supply ports and alsotWo series of graduated exhaust ports, check valves to coperate withsaid supply and exhaust ports, and means for simultaneously opening oneseries of supply ports and throttling the other series when the platformis being lifted and for simultaneously opening one series of exhaustports and throttling the other When the platform is descending.

21. The combination with aplatform, (of '130' CII a plurality of motorsfor lifting the same, a plurality of valves for, controlling saidmotors, check valves associated with the aforesaid valves, planetarygearing for -actuating said first-named valves, and means connected tothe platform for operating said gearing.

22. 1n Valve mechanism, the combination with a hollow valve having twosets of ports at each end, of a valve casing having chamberscoperatingwith said ports, and check valves in said chambers, the ports an dvalves being constructed and arranged to cause the supply to pass intothe interior of said hollow valve, out of the same through' certain setsof ports, and past certain check valves, and the exhaust lto pass theother check valvesint'o the interior of the hollow valve, and thence outof same.

23. The combination-with a platform, of

a plu lality of hydraulic motors for lifting the same, a plurality ofvalves each .'havmg four series of ports, planetary differential 'andsaid differential gear mechanisms, said tensional connectionscorresponding `in number to the number of sald motors, and check valveslnterposed between sald valves and said motors, the number of said checkvalves corresponding in number to the number of Series of ports in saidfirst-named valve.

In testimony whereof, I have signed'my name to this specification in thepresence of two subscribing witnesses.

ANDREW M. COYLE.

Titnesses CHARLES M. NIssEN, HENRY E. KIRBY.

